Question

该程序不起作用，我想进行二分搜索，但只是在开始时它给了我全局错误。它说“搜索”没有定义。请帮助我，我的整个讲座都坚持下去。

def bsearch (s, e, first, last):
  print first, last
  if (last - first) < 2: return s[first] == e or s[last] == e
  mid = (last - first) + (last - first)/2
  if s[mid] == e: return True
  if s[mid] > e: return bsearch(s, e, first, mid - 1)
  return bsearch(s, e, mid + 1, last)

def search1 (s, e):
  print bsearch(s, e, 0, len(s) - 1)
  print 'Search complete'

def testSearch():
  s = range(0,1000000)
  raw_input('basic, -1')
  print search(s,-1)
  raw_input('binary, -1')
  print search1(s,-1)
  raw_input('basic, end')
  print search(s,1000000)
  raw_input('binary, end')
  print search1(s,1000000)
  s = range(0,10000000)
  raw_input('basic, partway')
  print search(s,1000000)
  raw_input('basic, larger end')
  print search(0,10000000)

>>> testSearch()
basic, -1

Traceback (most recent call last):
  File "<pyshell#10>", line 1, in <module>
    testSearch()
  File "C:\Users\bangash\Documents\python files\lec8.py", line 17, in testSearch
    print search(s,-1)
NameError: global name 'search' is not defined

Answer 1

您的测试用例似乎在比较search和search1

的效果

所以我想search应该是一个尚未定义的线性（即基本）搜索函数

例如：

def search(s, e):
    for item in s:
        if item == e:
            break
    print 'Search complete'

Answer 2

我没有看到您定义search的位置，但您确实将search1指定为函数，但是您的名字有误吗？

只需将所有search(s,-1)行更改为search1(s,-1)

Python全局名称错误

2 个答案: